Composite structures of Ru(bpy)(2)(4,4'-(PO3H2)(2)bpy)(2+) surface bound to nanocrystalline TiO2 with an overlayer of Ru(bpy)(3)(2+) ion exchanged into Nafion, FTOInanoTiO(2)-[Ru(bpy)(2)(4,4'-(PO3H2)(2)bpy)](2+)/Nafion,Ru(bpy)(3)(2+ ) (FTO = fluorine-doped tin oxide), have been prepared and characterized Steady-state emission and time-resolved lifetime measurements demonstrate that energy transfer occurs from Nafion,Ru(bpy)(3)(2+)* to adsorbed Ru(bpy)(2)(4,4'-(PO3H2)(2)bpy)(2+) with an efficiency of similar to 0 49 Energy transfer sensitizes photoinjection by the adsorbed metal-to-ligand charge transfer (MLCT) excited state by an "antenna effect"